The Aufbau Principle describes that O electrons with the same spin cannot occupy the same orbital.
electrons will occupy single orbitals within and energy level before doubling up
electrons fill lower energy levels first before occupying higher energy levels.
O electrons in the same level have the same amount of energy

electrons fill lower energy levels first before occupying higher energy levels.

Explanation:

The Aufbau's principle describes that electrons fill lower energy levels first before occupying higher energy levels.

In writing the electronic configuration of atoms, the Aufbau's principle is one of the most important principles to consider.

It states that "sublevels with with lower energies are filled up before those with higher energies".

Sublevels do not fill up in numerical order.

definition

                    entropy is a measure of the randomness or the extent of disorder of a chemical process.

                      enthalpy is a measure of the heat change of a reaction occurring at a constant pressure.

measurement units:

                        entropy is measured in joule per kelvin (jk⁻¹)   whereas enthalpy is measured in joule per mole (jmol⁻¹)

requirements:

                            entropy has no requirements or limits, and its change is measured by the division between the heat change of the chemical process and the temperature.

                              in contrast, enthalpy can only be related to the heat change of the reaction under standard conditions.